Tributes have been placed at the site where two teenage girls were killed in a horror crash early Sunday morning at Anstead in Brisbane's southwest.

Police say it appears the girls' sedan smashed into a power pole in Hawkesbury Road about 3.30am.

Samantha Neilsen and Zara Simon. Photo: Supplied

Teenagers, Samantha Neilsen and Zara Simon, were believed to be the only occupants of the car.

Advertisement

The Forensic Crash Unit is investigating speed as a possible cause of the accident.

By late Sunday afternoon, local residents had begun to put flower tributes at the scene of the crash.

A roadside trbute to Samantha Neilsen and Zara Simon.

Anstead resident Patrick Wood said family groups were among those who began arriving after police and emergency crews left about 2pm.

"As I saw people turning up, they were taking a few moments to pause and reflect," Mr Wood said.

"There was even a family, with I think four children - a husband and a wife with four children - they took flowers. That was touching.

The view down Hawkesbury Road, which Anstead residents say was resurfaced this year with "catseye" reflectors installed. Photo: Supplied

"I saw two groups of people, so I think they may have been known by other locals."

Mr Wood said the road conditions on Hawkesbury Road were good and the rural road had "catseye" reflectors down the middle of the road.

"The road conditions are good particularly after the resurfacing of Hawksbury Road in 2012," he said.

"There are catseyes in the centre of the road in that section (where the crash occurred) and not on the shoulders.

"Light could be better, but it is a rural road and locals know it."

One friend of the pair, Shay Tolhoek, has created a video tribute to the girls and posted it on YouTube.

The video shows a collection of photos of the girls in happier times, smiling and laughing, to the song Forever Young played by Ms Tolhoek on the ukulele.

"Thank you for blessing all our lives just by being yourself," Ms Tolhoek says at the beginning of the short clip.

Other friends have paid tribute to the girls on Facebook.

"It's been 24 hours since Zara Simon and Samantha Neilsen where taken away from us in such a tragic event. Forever in our heart, you have moved a whole community not just family and friends," one friend wrote.

Another said: "Still can't believe that it happened, life really is a fragile thing. Even though I only new you for a year, you where a mad chick to hang out with! R.I.P Zara Simon, thinking of you."